Fishing waste: a potential new source of biodegradable plastic

By: Dana Sackett, PhD

The prestigious James Dyson Award is given to a university student each year for an invention that helps solve a widespread problem.  Lucy Hughes, the 2019 winner of this award, may have outdone herself by potentially solving not one but two global issues with her innovative design.  She proposed using the waste from fish processing (such as fish skin and scales) to produce biodegradable plastic.

Lucy Hughes holds a piece of a biodegradable plastic made from fishing waste. Dyson Source

Before we delve any further into how she invented such a novel product, let’s discuss the global problems her product could help fix.  First, the discarding of fish carcasses, skin, and scales after fish are harvested and processed has been recognized as an important source of waste and pollution. To help with this issue, fish byproducts have been used to create fishmeal (a product used to add nutrition to domestic animal feed), fish oil, and organic fertilizers. Despite these uses, more than half of the material from harvested fish are still discarded, creating between 30 and 60 million tons of waste a year.

A fish processing plant. Source

The other problem Hughes’s invention may be able to help with is plastic. Plastic is a topic we have covered here at The Fisheries Blog before (see here, here and here).  In an effort to be brief, I will sum-up some of the major environmental problems that come from our global overuse of plastic. After serving relatively brief uses, most plastics end-up in landfills and aquatic ecosystems, often taking centuries to degrade. This has led to plastic clogging our ecosystems and all to frequent media images of dead birds with guts full of plastic, sea turtles eating plastic bags or being impaled by plastic straws, and waves and ocean gyres full of plastic. Some unseen problems that arise from plastic trash include the contaminants that make-up plastic and the ones that often glom-on to bits of plastic trash in the environment; giving a double-whammy of toxic exposure to any individual that is unlucky enough to mistake plastic in the environment for food. 

News articles on plastic trash in the ocean. A surfer surrounded by trash in Indonesia (left; source), a dead albatross found on Midway Atoll with a stomach full of plastic (center; picture by Chris Jordan; source), a sea turtle eating plastic debris (right; source).

So how did Hughes come-up with the idea that fish waste could be used to make plastic? Well, she noticed when visiting a fish processing plant near her university how pliable fish skin and scales were.  She set off from there to figure out what type of binding agent would hold the natural materials together. After testing numerous different possibilities, she found red algae, a natural ingredient commonly used in agar (the jelly-like substance in the bottom of petri dishes) and some food items, seemed to work best.  Her discovery resulted in a flexible, translucent, plastic-like sheeting that could biodegrade in four to six weeks.  Because creating this material only took a small amount of heat, making the plastic-like sheeting also took very little energy. Even more impressive, the waste from a single Atlantic cod has been equated to making approximately 1400 biodegradable plastic-like bags.

Nature/Rochman, Browne et al. 2013

Hughes’s product has the potential to help with at least two global issues: using fish waste that would otherwise be thrown away, replacing plastic with a biodegradable alternative that is easy to produce, and doing so using little energy.  I am thankful that Lucy Hughes was given the opportunity to develop her ideas and hope that more of the bright minds out there are given the same opportunity to thrive so they can share their problem-solving ideas with the world.

References and other useful information

Archer M, Watson R, Denton JW. 2001. Fish Waste Production in the United Kingdom – The Quantities Produced and Opportunities for Better Utilisation. Seafish Report No. SR537. Sea Fish Industry Authority.

Arvanitoyanni IS, Kassaveti A. 2008. Fish industry waste: treatments, environmental impacts, current and potential uses. International Journal of Food Science and Technology 2008, 43, 726–745.

Choy CA, Drazen JC. 2013. Plastic for dinner? Observations of frequent debris ingestion by pelagic predatory fishes from the central North Pacific. MEPS 485:155-163.

Cozar A, Echevarria F, Gonzalez-Gordillo JI, Irigoien X, Ubeda B, Hernandez-Leon S, Palma AT, Navarro S, Garcia-de-Lomas J, Ruiz A, Fernandez-de-Puelles ML, Duarte CM. 2014. Plastic debris in the open ocean. 111:10239-10244. 

http://www.pnas.org/content/111/28/10239.full

Rochman, C., et al. 2013. Ingested plastic transfers hazardous chemicals to fish and induces hepatic stress. Scientific Reports 3: 3263

Rochman, C., Browne, A. et al. 2013. Comment: Classify plastic waste as hazardous. Nature 494: 169-171

https://www.fao.org/state-of-fisheries-aquaculture

https://www.bbc.com/news/newsbeat-50419047

https://www.globalcitizen.org/en/content/world-wastes-50-million-tons-of-fish-each-year/

https://www.theguardian.com/environment/2018/jul/09/one-in-three-fish-caught-never-makes-it-to-the-plate-un-report

https://www.fao.org/flw-in-fish-value-chains/value-chain/processing-storage/processing-plants/regulatory-environment/en/

https://www.fao.org/flw-in-fish-value-chains/resources/resources/Preventing-Waste-in-the-Fish-Processing-Supply-Chain

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